Study On The Synthesis Of 1,3-diaryl-2-pyrazoline And Cationic Fluorescent Whitening Agent

1,3-diaryl-2-pyrazoline and their cationic fluorescent whitening agents are important substances in many industries, such as plastic,detergent,soap,paper making,synthetic fibre and textile printing and dyeing industry etc. There is the important trend in the development of fluorescent whitening agent that man will have amorphous products change to crystal. In the result, Improved the extrinsic feature and whitening effects. On the same time, it is easy that the pyrazoline become the pyrromonazole through dehydrogenation in the course of chlorine bleach. So man insert the substituent to benzene or pyrazoline in order to improve the wet photostability. On the other hand, 1,3-diaryl-2-pyrazoline is the important medical intermediate. In this paper, I study on the synthetic method in the 1,3-diaryl-2- pyrazoline. Through the different materials and routes, we got a series of different substituent pyrazoline that have good fluorescent white effect. We proved the fluorescent white effect by the fluorescence test. There are three synthetic methods in the preparation of 1,3-diaryl-2-pyrazoline: Mannich alkali and aromatic hydrazine condensation, α,β-unsaturated ketone and aromatic hydrazine, use the known 1,3-diaryl-2-pyrazoline. Through the above three methods, prepared 1-(4-dimethylamino-ethylsulfonylphenyl)-3-(4-chloro- phenyl)- 2- pyrazoline,5-phenyl-1-(4-dimethylamino-ethyl sulfonyl phenyl)-3- (4-chloro -phenyl)-2- pyrazoline and 1-(4-dihydroethyl amino-ethylsulfonyl-phenyl)-3-(4- chloro-phenyl)-2- pyrazoline, The yield of the pyrazoline is 75-80%. The compound structure is proved by IR,1H-NMR. Use these compounds respectively react with phosphoric acid,formic acid,amidosulphonic acid in the solvent such as ethanol,water,acetic acid, we got six different cationic fluorescent whitening agents. The products have good water solubility and bring the intense blue and purple fluorescence.Prepared the 4-vinylsulfonyl-phenylamine by the para-easter hydrolytic decomposition, then react with dimethylamine, we prepared the 4- di methyl amino- ethanylsulfonyl-phenyl amine. Prepared the 4-dimethyl amino-ethanyl sulfonyl- phenylhydrazine through the amine diazotization,deoxidation. In the course of deoxidation, study on the reducing agent in the use of sodium bisulfite and tin chloride. Compare the two reducing agent with the superiority and shortage in the preparation. The yield of the product is 75%. Proved the compound structure by the IR,1H-NMR. Improved the yield of the product and Optimized the technological route by studying the technological conditions of the reaction. Prepared the 1-(4-chlorophenyl)-2-(4-morpholin)-ethanyl-ketone by the Mannich method. synthesized the 1-(4-chloro-phenyl)-3-phenyl-propenone by aldol conden- sation, the yield is 80-90%. Prepared 1-(4-dimethylamino-ethylsulfonylphenyl)-3-(4-chloro- phenyl)- 2- pyrazoline through the reaction of the mannich alkali with aromatic hydrazine, the route is not been reported; compared the route with β-chloro-ketone, the yield of the compound and the crystal of the product are better. Prepared 1-(4-dihydroethyl amino-ethylsulfonyl-phenyl)-3-(4-chlorophenyl)-2-pyrazoline through the reaction of the known the pyrazoline and diethanolamine, shorten the condensation route of aromatic hydrazine, improve the yield of the product. In the fluorescence spectrum of 1,3-diaryl-2- pyrazoline, 5-phenylpyrazoline have strong absorption peak and show strong fluorescence. But the long subsistent in the amino have weak absorption peak and show weak fluorescence.